An undertray trim panel configured as a diffuser in the rear region of a motor vehicle is generally disclosed in DE 10 2012 205 582 A1. Included is a lower flat element formed by way of a trim panel of the rear bumper and not ending freely, but rather curving forward in an arc. In motor vehicles having an internal combustion engine, for example in the front region, components can be situated in the engine compartment in front of, to the side of and, in particular, behind the internal combustion engine, which components are to be flowed around by cool air, in order to be cooled in an optimum manner. The air should be cooler than the air which tends to be warmer and has flowed through the front radiator and the associated fan and then flows through the remaining engine compartment, it being possible, however, for the latter air to be cool enough for other components, in particular those which lie closer to the engine. In general, however, the flat efficient submerged air intake device (FESAD) air inlet can also serve for other types of air supply for units or components, not only for cooling purposes.
In order to cool components with fresh air that lie behind the internal combustion engine, heat up during operation and must not become too hot, what is known as a NACA air inlet can be provided. The air inlet supplies air flow in the undertray trim panel and typically extends below the oil sump of the engine and opens into the space which lies behind the engine. A NACA air inlet usually requires certain minimum dimensions, however, in particular a certain length and height in relation to the vehicle longitudinal direction, in order to operate efficiently, and its lowermost part typically must be at a legally prescribed minimum spacing from the roadway. Therefore, a NACA air inlet typically restricts the packaging space available above it in the engine compartment.
Although the NACA air inlet in the abovementioned document DE 10 2012 205 582 A1 has a relatively low overall height, it is generally sufficient here because typically only a component which lies directly above it is to be cooled, namely a rear muffler which is additionally arranged in a housing, through which the supplied fresh air flows. In order that air flow can also pass satisfactorily onto components which lie further to the top in an engine compartment, the NACA air inlet would also have to reach as far as there, since otherwise a premature split of the cool air flow would take place, in particular as a result of the warmer air which circulates in the engine compartment and has flowed through the front radiator and the associated fan. Owing to its construction, the NACA air inlet commonly has a linearly obliquely running ramp with a correspondingly relatively large overall height.
It would be desirable to provide a motor vehicle undertray trim panel having an air inlet in such a way that the available packaging space in the engine compartment is increased both in the vertical and in the horizontal directions, and, moreover, with the result that components which lie in front of, to the side of or behind the internal combustion engine are supplied with cooling fresh air in an optimum manner. It would be desirable that this function be ensured in a manner which is as neutral as possible with regard to harmful resistances, such as vehicle air resistance.